Introduction to the new potato variety Zhongshu 7

Suitable range: For spring and autumn planting in the Central Plains double-cropping region of Beijing, Shanghai, Jiangsu, Zhejiang, Anhui, Jiangxi, Shandong and Henan, and for early-maturing winter cultivation in the southern winter-cropping region of Fujian, Guangdong and Guangxi.

Variety source: Selected through systematic breeding from the sexual cross of Zhongshu 2 x Jizhangshu 4.

Characteristics and traits

Early-maturing variety, with a growing period of 64 days after emergence. Plant type semi-erect, strong growth vigor, plant height 50 cm, leaves dark green, stems purple, corolla purplish red, tubers round, light yellow skin, milky white flesh, smooth skin, shallow eyes, short stolons, concentrated tuber set, marketable tuber rate 61.7%. Inoculation identification: moderately resistant to mild mosaic virus disease, highly resistant to severe mosaic virus disease, mildly to moderately susceptible to late blight. Tuber quality: fresh tuber vitamin C content 32.8 mg/100 g, starch content 13.2%, dry matter content 18.8%, reducing sugar content 0.20%, crude protein content 2.02%.

Yield performance: In the 2004-2005 national potato variety regional trial, the tuber yields per mu of the early-maturing Central Plains double-cropping group were 1653 kg and 1528 kg respectively, which were 8.2% lower and 26.1% higher than the control Dongnong 303 respectively, with a two-year average yield per mu of 1591 kg, 5.5% higher than the control Dongnong 303; the tuber yields per mu of the southern winter-cropping group were 1702 kg and 1437 kg respectively, which were 16.5% and 65.2% higher than the control Dongnong 303 respectively, with a two-year average yield per mu of 1570 kg, 34.6% higher than the control Dongnong 303. In the 2005 production trial of the early-maturing Central Plains double-cropping group, the tuber yield per mu was 1902 kg, 7.3% higher than the control Dongnong 303. This variety meets the national potato variety approval standards and has passed approval. It is an early-maturing fresh-eating variety, moderately resistant to mild mosaic virus disease, highly resistant to severe mosaic virus disease, and mildly to moderately susceptible to late blight.

Cultivation points

1. In the Central Plains double-cropping region, sow from early January to mid-to-late March in spring and harvest from May to late June; sow from early-to-mid August to early September in autumn, soak seed tubers in 5-8 mg/L gibberellin aqueous solution for 5-10 minutes before sowing, then cover with moist sandy soil for sprouting, and harvest from late October to early December; spring planting under plastic film can be appropriately earlier. In the southern winter-cropping region, sow from October to December. 2. Plant appropriately sparsely; for flat planting, row spacing 60-70 cm, plant spacing 25-30 cm, density 4000-4500 plants per mu. For seed-production fields, to increase the propagation coefficient, the density per mu can be increased to 6000-6500 plants. 3. Choose loose-textured, well-irrigated and well-drained plots for sowing; avoid continuous cropping, and do not rotate with other Solanaceae crops. Seed-production fields should be isolated from commercial potato production fields and other disease-source crops. Apply sufficient basal fertilizer, strengthen early-stage management after emergence, timely earth up and cultivate to promote early vigorous growth and early tuber set, irrigate promptly during the tuber-setting and tuber-bulking stages, and stop irrigation one week before harvest to facilitate harvesting and storage. 4. Suitable for intercropping and relay intercropping with crops such as cotton and corn. In the double-cropping region, for seed production, harvest appropriately early in spring, sow appropriately late in autumn, and pay attention to timely spraying to control aphids and removing diseased plants.